Cat Scratch Fever: Causes, Symptoms, and Diagnosis

If you have any contact with cats that are infected with the bacteria “Bartonella henselae”, there is a big chance that you will be infected with cat scratch fever.

cat scratch fever

Cats are sure adorable. Starting with their cute little ears, fluffy paws, and long tail, all cats are lovable. Let’s add up their playful nature as well. They are so funny when they try to catch a light, and they are so sweet when they sit on your lap. Cats may, perhaps, have not to be the man’s best friend, but they sure can make their own way to your hearts.

And if you are a cat lover, perhaps you buy or adopt cats at home. It’s wonderful that you take care of them, but you have to be careful as well. Did you ever hear of cat scratch fever?

What is cat scratch fever?

Cat scratch fever is a bacterial infection. It is also known with the name cat scratch disease (CSD). Usually, it comes from a cat scratch or bites. But any other form of contact with an infected cat can also cause it such as the cat’s saliva getting into the white of your eyes as well as your open wound. There are also cases where the disease is transferred by another carrier of the bacterium such as a tick or a flea. Humans can also transfer the bacterium.

If you have any contact with cats that are infected with the bacteria “Bartonella henselae”, there is a big chance that you will be infected with cat scratch fever.

Since 2018, the Centers for Disease Control and Prevention (CDC) reported an estimated 12,000 people that are diagnosed to be infected with CSD. Five hundred out of this estimation is hospitalized and even increase. The possible cause of the case is the increasing rate of adopting kittens.

So, anyone who have interactions with cats – may you be an owner or not – have the risk of having cat scratch fever.

The report came from CDC says that cat scratch disease is widespread in the southern area of US. It is common among children whose ages range from 5 to 9. Males have a higher percentage to be hospitalized although women are the most patient that diagnosed with it.

Cat scratch disease is not so serious unless your immune system is weakened. Thus, if you have HIV/AIDS, diabetes, and cancer, there is a high risk for you to have a serious case of cat scratch fever. Pregnant women and those who undergo organ transplant also fall into this category.

What are the symptoms of cat scratch disease?

1. In Cats

You can’t always tell which cat carries the bacterium B. henselae. For instance, even if they are infected with the bacterium, they don’t get ill.

Usually, cats got B. henselae from infected fleas. No wonder, humans can get infected directly from fleas’ bites.

CDC reported a 40% estimation of cats which serve as bacterium carriers. Most of these infected cats are kittens. As for treatment, experts do not usually recommend it.

2. In Humans

Catching a cat scratch fever will possibly result in the following common symptoms:

  • Body aches
  • Headaches
  • Fatigue
  • A blister or bump at the scratch or bite site
  • Inflamed lymph nodes near the scratch or bite
  • A low-grade fever (usually it is below 100.4°F but above 98.6°F.

Initially, you may notice a bump or blister on your skin 3 to 10 days after you have been exposed to the infection. The other symptoms such as a headache and swollen lymph nodes usually occur after several days or even weeks.

Cat scratch disease also has unusual symptoms which are:

  • Weight loss
  • A sore throat
  • Loss of appetite

The disease may also cause rare symptoms which are associated with a more severe form of the condition. These rare symptoms are:

  • Prolonged fever
  • Rash
  • Joint pain
  • Abdominal pain
  • Chills
  • A backache

Not Cat Scratch Fever

Cases that mistake a disease for cat scratch fever do exist. It is because of the seemingly similar symptoms that the disease exposing. However, if you check it further, you’ll know that the disease is not CSD.

The diseases that are mistaken for CSD are below:

  • Lyme disease

The infection from this disease comes from a tick. Initially, the symptoms that can be seen is a bulls-eye rash. Afterward, the patient will start to experience flu-like symptoms.

  • Lymphogranuloma Venereum

The infection in this disease is transmitted by sexual intercourse. It is mistaken for CSD because it causes skin lesion that may be blister or bump. Soon, the patient will have swollen lymph nodes.

  • Brucellosis

Like the other diseases, the symptoms that associated with this condition are flu-like symptoms followed by swollen lymph nodes. However, this disease was transferred from livestock to human and cats to human.

  • Lymphadenitis

It is a common inflammatory condition, which causes swollen lymph nodes.

How to diagnose and treat cat scratch fever?


Learning that symptoms associated with cat scratch fever also resulted from other diseases, it will be difficult to base the diagnosis in the symptoms alone. If your doctor thinks that you got CSD, the most appropriate diagnosis to conduct a physical examination. He or she will check for the presence of B. henselae bacterium by conducting PCR (Polymerase Chain Reaction) blood test.


CSD is not a serious condition, and therefore no treatment is required to conduct. Usually, from 1 to 2 weeks, the bump or blister will be visible. The swollen lymph nodes, on the other hand, usually last up to 4 months. In rare cases, it takes 6 months to 1 year before it disappears. It may also lead to other issues.

However, those who have serious cases and have weak immune system have to take antibiotics.

Swollen lymph node can be treated using azithromycin (Zithromax). Usually, you will treat CSD using this medication for 5 days. But other antibiotics are also available for infection treatment. These are:

  • Trimethoprim-sulfamethoxazole (Bactrim, Septra)
  • Tetracycline (Sumycin)
  • Rifampin (Rifadin)
  • Ciprofloxacin (Cipro)

For how long the drug will be used differ on each case. It may be for 5 days only or it may last up to 2 weeks. For possible medication interaction, including alcohol consumption, speak with your doctor.

cat scratch fever

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